DBIx::Class::Schema::Versioned - DBIx::Class::Schema plugin for Schema upgrades |
DBIx::Class::Schema::Versioned - DBIx::Class::Schema plugin for Schema upgrades
package Library::Schema; use base qw/DBIx::Class::Schema/; # load Library::Schema::CD, Library::Schema::Book, Library::Schema::DVD __PACKAGE__->load_classes(qw/CD Book DVD/);
__PACKAGE__->load_components(qw/+DBIx::Class::Schema::Versioned/); __PACKAGE__->upgrade_directory('/path/to/upgrades/'); __PACKAGE__->backup_directory('/path/to/backups/');
sub backup { my ($self) = @_; # my special backup process }
sub upgrade { my ($self) = @_;
## overridable sub, per default just runs all the commands.
$self->run_upgrade(qr/create/i); $self->run_upgrade(qr/alter table .*? add/i); $self->run_upgrade(qr/alter table .*? (?!drop)/i); $self->run_upgrade(qr/alter table .*? drop/i); $self->run_upgrade(qr/drop/i); $self->run_upgrade(qr//i); }
This module is a component designed to extend the DBIx::Class::Schema manpage
classes, to enable them to upgrade to newer schema layouts. To use this
module, you need to have called create_ddl_dir
on your Schema to
create your upgrade files to include with your delivery.
A table called SchemaVersions is created and maintained by the module. This contains two fields, 'Version' and 'Installed', which contain each VERSION of your Schema, and the date+time it was installed.
If you would like to influence which levels of version change need
upgrades in your Schema, you can override the method ddl_filename
in the DBIx::Class::Schema manpage. Return a false value if there is no upgrade
path between the two versions supplied. By default, every change in
your VERSION is regarded as needing an upgrade.
The actual upgrade is called manually by calling upgrade
on your
schema object. Code is run at connect time to determine whether an
upgrade is needed, if so, a warning ``Versions out of sync'' is
produced.
NB: At the moment, SQLite upgrading is rather spotty, as SQL::Translator::Diff returns SQL statements that SQLite does not support.
This is an overwritable method which is called just before the upgrade, to
allow you to make a backup of the database. Per default this method attempts
to call $self->storage->backup
, to run the standard backup on each
database type.
This method should return the name of the backup file, if appropriate.
backup
is called from upgrade
, make sure you call it, if you write your
own <upgrade> method.
This is an overwritable method used to run your upgrade. The freeform method
allows you to run your upgrade any way you please, you can call run_upgrade
any number of times to run the actual SQL commands, and in between you can
sandwich your data upgrading. For example, first run all the CREATE
commands, then migrate your data from old to new tables/formats, then
issue the DROP commands when you are finished.
$self->run_upgrade(qr/create/i);
Runs a set of SQL statements matching a passed in regular expression. The
idea is that this method can be called any number of times from your
upgrade
method, running whichever commands you specify via the
regex in the parameter.
Use this to set the directory your upgrade files are stored in.
Use this to set the directory you want your backups stored in.
Returns the current schema class' $VERSION; does -not- use $schema->VERSION since that varies in results depending on if version.pm is installed, and if so the perl or XS versions. If you want this to change, bug the version.pm author to make vpp and vxs behave the same.
Jess Robinson <castaway@desert-island.demon.co.uk>
DBIx::Class::Schema::Versioned - DBIx::Class::Schema plugin for Schema upgrades |